Cabazitaxel exhibits notable anticancer and antileukaemic properties. Cabazitaxel, chemically known as 4-acetoxy-2α-benzoyloxy-5β,20-epoxy-1-hydroxy-7β 10β-dimethoxy-9-oxo-tax-11-en-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionate and is represented by the following structural formula:

The compound was disclosed in U.S. Pat. No. 5,847,170 (hereinafter referred as US' 170). It is sold under brand name Jevtana as its acetone solvate. Cabazitaxel is prepared according to the method which is described more particularly in US' 170.
Although Cabazitaxel is a very important second line treatment for the metastatic CRPC, there are still limited reports on the synthesis of Cabazitaxel. Aventis reported the first synthetic route of Cabazitaxel in US' 170 starting from 10-deacetylbaccatin III (10-DAB). The synthesis consisted of more than five steps with a very low reported yield.
U.S. Pat. No. 5,962,705 disclosed a process for the taxoid derivatives using alkylating agents such as alkyl halide, alkyl sulfate, oxonium in the presence of an anionization agent.
CN 102060815 provided a method for the conversion of Docetaxel to Cabazitaxel by using dimethylsulfate as an alkylating agent in a weakly alkaline organic solvent (pyridine).
CN 102285947 reported the synthesis of Cabazitaxel by methylating the 7 and 10-OH in 10-DAB simultaneously to furnish 7,10-dimethyl-10-DAB, which was then coupled with a protected (3R,4S)-β-lactam followed by deprotection of the 2′-OH, the total yield is approximately 18.0% for 3 steps.
Thus, there is a need for developing a process for preparation of cabazitaxel and its key intermediates which is not only feasible at industrial scale but also meets economics of scale in terms of yield.